Is this shorted board recoverable?

[korsen]

Greets all. I'm looking for expert information. None of you A+ jerks.

#1 - I've shorted out a motherboard before many years ago without standoffs. That computer reset itself every 3 seconds. Anything connected via a slot was destroyed. Anything connected via a wire was recoverable.

#2 - My brother's computer: ASUS P5W DH Deluxe. He spilled beer into a blowhole case fan which spilled onto my 2900Pro. My brother says the entire thing is shot. His power supply is destroyed, because I have a PSU tester. My 2900Pro he got beer on, also works. I'm using it at this very second. So I know that it's an isolated short somewhere. I scrubbed the old beer off my 2900 where I could see it, and everything worked fine. I cannot see a single drop of dried beer on the mobo. A few of the solder spots on the mobo (not the underside) are copper colored, but i'm assuming this is from heat.

#3 - When I put MY power supply in and leave the 4-pin regulator out, everything turns on nicely and spins at the highest RPM, obviously indicating something is missing - my point being that it runs. When I add the 4-pin, all the LED's blink and it shuts off instantly. The PSU tester will not turn on the PSU until it has been off for a few seconds without electricity. The LED on the motherboard never falters however.

#4 - What I don't understand, is that if the beer spilled on the right side of the motherboard, where the ram, 24-pin connector, and end of the GPU is (as well as it's own power connections), and the computer turns on without the 4-pin, why then does it fail if the 4-pin is on the very upper left side where it would be impossible to get liquid in such a fashion?

I haven't scrutinized all the solder points yet but I doubt scrubbing the dirty looking solder i've found will fix my problem, so hence, this post.

Cheers.

 

[vvhocare5]

The issue with beer (or soda) is that it leaves a film behind inside the connectors and cables thats what interferes with the signals. It doesnt matter if its on top of the card - its in all of the little places.

What you are trying to answer is what would make the mb behave this way - unfortunately no one can predict the failure mechanism when it is confused.

The trick is you have to clean it before the beer dries or there is no hope

 

[korsen]

The motherboard is so clean it looks like it was given a wax job. My GPU however, which is working, had clearly visible dried beer on it. So why then does my GPU work and the motherboard does not? I'm looking for an electrical answer as to why the 24-pin alone will boot everything up (but doesn't actually work) and adding the 4-pin turns everything off instantly after the power button has begun the power up sequence. I'm wondering why there isn't a power interrupt between the power switch and the 24-pin, but there is an interrupt from the 4-pin.

 

[GhislainG]

Did beer get anywhere near or under the CPU?

 

[ko888]

The 4-pin ATX12V connection provides the power for the CPU hence its location next to the VRMs that are underneath the VRM cooler heat-pipe assembly. If it's left unconnected the CPU won't receive any power so the system won't boot up. Other components on the motherboard are powered from the 24-pin EATXPWR connector (i.e. on a different power circuit than the CPU's).

Your statement "the 24-pin alone will boot everything up (but doesn't actually work)" doesn't make sense. If the 24-pin EATXPWR connection boots everything up then the complete system is receiving sufficient power to work. I don't see how that is possible since the CPU gets its power from the separate 4-pin ATX12V connection which you say isn't connected.

 

[korsen]

while the 4-pin isn't connected to the board, all the fans light up and spin, heatsink fan spins, 1650pro (ati) spins at high rpm, but I get no boot or POST screens and no video. while the 4-pin IS connected, all the lights go on for a split second and the fans begin spinning as well, and then it all dies immediately and stays that way.

@Ghislain: It doesn't look like any would have fallen directly on the processor, though it had to have fallen through a spinning 80mm fan so it can't be likely much got in there cause everything looks clean as can be around the processor save for dust on the fan.

 

[GhislainG]

I would take the motherboard out and remove all parts, including the CPU. I would then carefully inspect the motherboard. If everything looks fine and clean, then I'd reinstall the CPU, one RAM module and a video card to see if the system stays up outside of the case. If it doesn't, then the motherboard or the CPU may be defective. As pointed out above, testing without applying power to the CPU doesn't prove much.